Playback based on number of listeners

ABSTRACT

Systems, methods, and apparatus to process audio signals based on a number of listeners are disclosed. An example implementation involves a playback device processing, via an audio processing component, an audio signal for playback according to a first audio characteristic. While processing the audio signal for playback according to the first audio characteristic, the playback device detects, via a location component, a number of listeners in a listening area. The playback device determines a second audio characteristic based on the detected number of listeners in the listening area, and after determining the second audio characteristic, processes, via the audio processing component, the audio signal for playback according to the second audio characteristic.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. non-provisional patentapplication Ser. No. 15/166,241, filed on May 26, 2016, entitled“Playback Based on Wireless Signal,” which is incorporated herein byreference in its entirety. U.S. non-provisional patent application Ser.No. 15/166,241 is a continuation of U.S. non-provisional patentapplication Ser. No. 15/056,553, filed on Feb. 29, 2016, entitled“Location Determination According To Auditory Tones,” which isincorporated herein by reference in its entirety. U.S. non-provisionalpatent application Ser. No. 15/056,553 is a continuation of U.S.non-provisional patent application Ser. No. 14/726,921, filed on Jun. 1,2015, entitled “Sound Field Calibration Using Listener Localization,”which is also incorporated herein by reference in its entirety. U.S.non-provisional patent application Ser. No. 14/726,921 is a continuationof U.S. non-provisional patent application Ser. No. 13/340,126, filed onDec. 29, 2011, entitled “Sound Field Calibration Using ListenerLocalization,” which issued as U.S. Pat. No. 9,084,058 on Jul. 14, 2015,and which is also incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The disclosure is related to consumer electronics and, moreparticularly, to systems, methods, and apparatus to continuouslycalibrate audio fields.

BACKGROUND

Home theater systems allow the listener to enjoy the cinema experiencewhile in the comfort of their home. To deliver the best possible sound,the systems allow the listener to adjust the sound field, volume andvarious Digital Signal Processing (DSP) effects.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the presently disclosed technologyare better understood with regard to the following description, appendedclaims, and accompanying drawings where:

FIG. 1 shows an illustration of an example system in which embodimentsof the methods and apparatus disclosed herein may be implemented;

FIG. 2A shows an illustration of an example zone player having abuilt-in amplifier and speakers;

FIG. 2B shows an illustration of an example zone player having abuilt-in amplifier and connected to external speakers;

FIG. 2C shows an illustration of an example zone player connected to anA/V receiver and speakers;

FIG. 3 shows an illustration of an example controller;

FIG. 4 shows an internal functional block diagram of an example zoneplayer;

FIG. 5 shows an internal functional block diagram of an examplecontroller;

FIG. 6 shows an example pair of zone players having mid-tweeter-mid(MTM) speaker arrangements, including audio filters, and configured as astereo pair;

FIG. 7 is a flowchart representative of an example method to implementthe example apparatus; and

FIG. 8 is a flowchart representative of an example method to implementthe example apparatus.

In addition, the drawings are for the purpose of illustrating exampleembodiments, but it is understood the present disclosure is not limitedto the arrangements and instrumentality shown in the drawings.

DETAILED DESCRIPTION

I. Overview

Example systems, methods, and apparatus to calibrate sounds fields aredisclosed herein. Real-time sound calibration is achieved throughlocalizing the position of the listener. In some examples, a locationsensor such as a video camera and infrared camera detect the position ofthe listener and then the home theater system software adjusts the soundfield. Example systems, methods, and/or apparatus disclosed herein alsoprovide localizing the position of the listener through analyzingpackets with associated timestamps. The example systems, methods, and/orapparatus disclosed herein may be used in combination with amultiple-speaker configuration in which the speakers included in theconfiguration share one or more sources of audio information and playthe audio in synchrony.

Some example systems, methods, and/or apparatus provide firsttriangulating the position of the listener in the listening zone byprocessing data gathered by location sensors in the listening zone inreal-time. Accordingly, such example systems, methods, and/or apparatusprovide an audio circuit capable of generating an improved sound fieldadjusted for the position of the listener. This real-time listenertriangulation allows for potentially increased aesthetics in the soundexperienced by the listener.

An example method implemented in accordance with the disclosure includesreceiving infrared signals through an infrared receiver and video datacaptured through a video camera at the location sensor, processing thereceived infrared signals and video data to triangulate the position ofthe listener via a triangulation algorithm, and generating, through anaudio processing component, audio characteristics of a sound fieldmodified by the position of the listener to play through a speaker.

In some embodiments, the location sensors are continuously receivinglocation data, wherein the continuous receiving of location data allowsfor tracking the position of the listener as the listener moves enablingreal-time sound field calibration.

An example embodiment of apparatus implemented in accordance with thepresent disclosure includes depth sensors to scan the listening zone, anaudio processing component to modify an audio input signal with thelocation information to form a sound field, first and second audiospeakers having first audio characteristics, and a third audio speakerhaving second audio characteristics, wherein the third speaker ispositioned between the first and second audio speakers. Some exampleapparatus include a digital audio processor to implement the first andsecond audio characteristics.

In some embodiments, the location sensors include infrared and imagecameras which receive infrared signals and image frame data. In someembodiments, the sensors include microphones which receive acoustic waveinformation. In some embodiments, the acoustic wave information includesa timestamp. In some embodiments, the location sensors receive packetswith an associated RSSI signal. In some embodiments, a combination ofdepth sensors is utilized.

In some embodiments, the apparatus further includes a network interfaceto receive at least one of the audio input signals, a synchronizationsignal associated with a multiple-device arrangement, or configurationsignal associated with a multiple-device arrangement. In some suchembodiments, the second speaker is to be positioned on the outside whenin a multiple-device configuration.

In some embodiments, the apparatus further includes a network interfaceto synchronize the first and second audio output with another audiodevice. In some such embodiments, the network interface is to receive atleast one of the audio signal or a user input.

Although the following discloses example systems, methods, and apparatusincluding, among other components, firmware and/or software executed onhardware, it should be noted such systems, methods, and/or apparatus aremerely illustrative and should not be considered as limiting. Forexample, it is contemplated any or all of these firmware, hardware,and/or software components could be embodied exclusively in hardware,exclusively in software, exclusively in firmware, or in any combinationof hardware, software, and/or firmware. Accordingly, while the followingdescribes example systems, methods, and/or apparatus, the examplesprovided are not the only way(s) to implement such systems, methods,and/or apparatus.

When any of the appended claims are read to cover a purely softwareand/or firmware implementation, at least one of the elements in at leastone example is hereby expressly defined to include a tangible mediumsuch as a memory, digital versatile disk (DVD), compact disc (CD),Blu-ray, and so on, storing the software and/or firmware.

These embodiments and many additional embodiments are described morebelow. Further, the detailed description is presented largely in termsof illustrative environments, systems, procedures, steps, logic blocks,processing, and other symbolic representations which directly orindirectly resemble the operations of data processing devices coupled tonetworks. These process descriptions and representations are typicallyused by those skilled in the art to most effectively convey thesubstance of their work to others skilled in the art. Numerous specificdetails are set forth to provide a thorough understanding of the presentdisclosure. However, it is understood to those skilled in the artcertain embodiments of the present disclosure may be practiced withoutcertain, specific details. In other instances, well known methods,procedures, components, and circuitry have not been described in detailto avoid unnecessarily obscuring aspects of the embodiments.

Reference herein to “embodiment” means a particular feature, structure,or characteristic described in connection with the embodiment may beincluded in at least one example embodiment of the invention. Theappearances of this phrase in various places in the specification arenot necessarily all referring to the same embodiment, nor are separateor alternative embodiments mutually exclusive of other embodiments. Assuch, the embodiments described herein, explicitly and implicitlyunderstood by one skilled in the art, may be combined with otherembodiments.

II. Example Environment

Referring now to the drawings, in which like numerals may refer to likeparts throughout the figures, FIG. 1 shows an example systemconfiguration 100 in which one or more of the method and/or apparatusdisclosed herein may be practiced or implemented. By way ofillustration, the system configuration 100 represents a home withmultiple zones. Each zone, for example, represents a different room orspace, such as an office, bathroom, bedroom, kitchen, dining room,family room, home theater room, utility or laundry room, and patio.While not shown here, a single zone may cover more than one room orspace. One or more of zone players 102-124 are shown in each respectivezone. A zone player 102-124, also referred to as a playback device,multimedia unit, speaker, and so on, provides audio, video, and/oraudiovisual output. A controller 130 (e.g., shown in the kitchen forpurposes of illustration) provides control to the system configuration100. The system configuration 100 illustrates an example whole houseaudio system, though it is understood the technology described herein isnot limited to its particular place of application or to an expansivesystem like a whole house audio system 100 of FIG. 1.

FIGS. 2A, 2B, and 2C show example illustrations of zone players 200-204.The zone players 200-204 of FIGS. 2A, 2B, and 2C, respectively, maycorrespond to any of the zone players 102-124 of FIG. 1. While certainembodiments provide multiple zone players, an audio output may begenerated using only a single zone player. FIG. 2A illustrates a zoneplayer 200 including sound producing equipment 208 capable of generatingsound or an audio output corresponding to a signal received (e.g.,wirelessly and/or via a wired interface). The sound producing equipment208 of the zone player 200 of FIG. 2A includes a built-in amplifier (notshown in this illustration) and speakers (e.g., a tweeter and twomid-range speakers). In certain embodiments, the zone player 200 of FIG.2A may be configured to play stereophonic audio or monaural audio. Insome embodiments, the zone player 200 of FIG. 2A may be configured as acomponent in a combination of zone players to play stereophonic audio,monaural audio, and/or surround audio. As described in greater detailbelow, in some embodiments, the example zone player 200 of FIG. 2A mayalso transmit a second signal to, for example, other zone player(s) inthe same or different zone(s), speaker(s), receiver(s), and so on.Transmission of the second signal may be part of, for example, a systemin which multiple zone players, speakers, receivers, and so on, form anetwork to, for example, present media content in a synchronization ordistributed manner.

The example zone player 202 of FIG. 2B includes a built-in amplifier(not shown in this illustration) to power a set of detached speakers210. The speakers 210 of FIG. 2B may include, for example, any type ofloudspeaker. The zone player 202 of FIG. 2B may communicate a signalcorresponding to audio content to the detached speakers 210 via wiredand/or wireless channels. Instead of receiving and generating audiocontent as in FIG. 2A, the zone player 202 of FIG. 2B receives the audiocontent and transmits the same (e.g., after processing the receivedsignal) to the detached speakers 210. Similar to the example zone player200 of FIG. 2A, in some embodiments the zone player 202 may transmit asecond signal, for example, to other zone player(s) in the same ordifferent zone(s), speaker(s), receiver(s), and so on.

The example zone player 204 of FIG. 2C does not include an amplifier,but allows a receiver 214, or another audio and/or video type devicewith built-in amplification, to connect to a data network 128 of FIG. 1and to play audio received over the data network 128 via the receiver214 and a set of detached speakers 216. In addition to the wiredcouplings shown in FIG. 2C, the detached speakers 216 may receive audiocontent via a wireless communication channel between the detachedspeakers 216 and, for example, the zone player 204 and/or the receiver214. In some embodiments the zone player 202 may transmit a secondsignal to, for example, other zone player(s) in the same or differentzone(s), speaker(s), receiver(s), and so on.

Example zone players include a “Sonos Play:3,” “ZonePlayer® 120,” and“ZonePlayer® 90,” which are offered by Sonos, Inc. of Santa Barbara,Calif. Any other past, present, and/or future zone players mayadditionally or alternatively be used to implement the zone players ofexample embodiments disclosed herein. A zone player may also be referredto herein as a playback device, and a zone player is not limited to theparticular examples illustrated in FIGS. 2A, 2B, and 2C. For example, azone player may include a wired or wireless headphone. In otherexamples, a zone player might include a subwoofer. In yet otherexamples, a zone player may include a sound bar. In an example, a zoneplayer may include or interact with a docking station for an Apple iPod™or similar device. In some embodiments, a zone player may relay one ormore signals received from, for example, a first zone player to anotherplayback device. In some embodiments, a zone player may receive a firstsignal and generate an output corresponding to the first signal and,simultaneously or separately, may receive a second signal and transmitor relay the second signal to another zone player(s), speaker(s),receiver(s), and so on. Thus, an example zone player described hereinmay act as a playback device and, at the same time, operate as a hub ina network of zone players. In such instances, media contentcorresponding to the first signal may be different from the mediacontent corresponding to the second signal.

FIG. 3 shows an example illustration of a wireless controller 300 in adocking station 302. The controller 300 may correspond to thecontrolling device 130 of FIG. 1. The controller 300 is provided with atouch screen 304 which allows a user to interact with the controller300, for example, to retrieve and navigate a playlist of audio items,control operations of one or more zone players, and provide overallcontrol of the system configuration 100. In some examples, the wirelesscontroller 300 may be used to group zone players into stereo and/orother multiple-device configurations. In certain embodiments, any numberof controllers may be used to control the system configuration 100. Incertain embodiments, there may be a limit on the number of controllerswhich may control the system configuration 100. The controllers might bewireless like wireless controller 300 or wired to the data network 128.Furthermore, an application running on any network-enabled portabledevice, such as an iPhone™, iPad™, Android™ powered phone, or any othersmart phone or network-enabled device may be used as a controller byconnecting to the data network 128. An application running on a laptopor desktop PC or Mac may also be used as a controller. Examplecontrollers include a “Sonos® Controller 200,” “Sonos® Controller foriPhone,” “Sonos® Controller for iPad,” “Sonos® Controller for Android,“Sonos® Controller for Mac or PC,” which are offered by Sonos, Inc. ofSanta Barbara, Calif. The flexibility of such an application and itsability to be ported to a new type of portable device is advantageous.

Referring back to the system configuration 100 of FIG. 1, a particularzone may contain one or more zone players. For example, the family roomof FIG. 1 contains two zone players 106 and 108, while the kitchen isshown with one zone player 102. Zones may be dynamically configured bypositioning a zone player in a room or space and assigning via thecontroller 130 the zone player to a new or existing zone. As such, zonesmay be created, combined with another zone, removed, and given aspecific name (e.g., “Kitchen”), if so programmed. The zone players 102to 124 are coupled directly or indirectly to a data network, such as thedata network 128 shown in FIG. 1. The data network 128 is represented byan octagon in the figure to stand out from other components shown in thefigure. While the data network 128 is shown in a single location, it isunderstood such a network may be distributed in and around the systemconfiguration 100.

Particularly, the data network 128 may be a wired network, a wirelessnetwork, or a combination of both. In some embodiments, one or more ofthe zone players 102-124 are wirelessly coupled to the data network 128based on a proprietary mesh network. In some embodiments, one or more ofthe zone players 102-124 are wirelessly coupled to the data network 128using a non-mesh topology. In some embodiments, one or more of the zoneplayers 102-124 are coupled via a wire to the data network 128 usingEthernet or similar technology. In addition to the one or more zoneplayers 102-124 connecting to the data network 128, the data network 128may further allow access to a wide area network, such as the Internet.

In certain embodiments, the data network 128 may be created byconnecting any of the zone players 102-124, or some other connectingdevice, to a broadband router. Other zone players 102-124 may then beadded wired or wirelessly to the data network 128. For example, a zoneplayer (e.g., any of zone players 102-124) may be added to the systemconfiguration 100 by simply pressing a button on the zone player itself,which enables a connection to be made to the data network 128. Thebroadband router may be connected to an Internet Service Provider (ISP),for example. The broadband router may be used to form another datanetwork within the system configuration 100, which may be used in otherapplications (e.g., web surfing). The data network 128 may also be usedin other applications, if so programmed. Further, in certainembodiments, the data network 128 is the same network used for otherapplications in the household.

In certain embodiments, each zone may play from the same audio source asanother zone or each zone may play from a different audio source. Forexample, someone may be grilling on the patio and listening to jazzmusic via zone player 124, while someone is preparing food in thekitchen and listening to classical music via zone player 102. Further,someone may be in the office listening to the same jazz music via zoneplayer 110 which is playing on the patio via zone player 124. In someembodiments, the jazz music played via zone players 110 and 124 isplayed in synchrony. Synchronizing playback amongst zones allows forsomeone to pass through zones while seamlessly listening to the audio.Further, zones may be put into a “party mode” where all associated zoneswill play audio in synchrony.

In certain embodiments, a zone contains two or more zone players. Forexample, the family room contains two zone players 106 and 108, and thehome theater room contains at least zone players 116, 118, and 120. Azone may be configured to contain as many zone players as desired, andfor example, the home theater room might contain additional zone playersto play audio from a 5.1 channel or greater audio source (e.g., a movieencoded with 5.1 or greater audio channels). If a zone contains two ormore zone players, such as the two zone players 106 and 108 in thefamily room, then the two zone players 106 and 108 may be configured toplay the same audio source in synchrony, or the two zone players 106 and108 may be paired to play two separate sounds in left and rightchannels, for example. In other words, the stereo effects of a sound maybe reproduced or enhanced through the two zone players 106 and 108, onefor the left sound and the other for the right sound. In certainembodiments, paired zone players may play audio in synchrony with otherzone players.

In certain embodiments, three or more zone players may be configured toplay various channels of audio which is encoded with three channels ormore sound. For example, the home theater room shows zone players 116,118, and 120. If the sound is encoded as 2.1 channel audio, then thezone player 116 may be configured to play left channel audio, the zoneplayer 118 may be configured to play right channel audio, and the zoneplayer 120 may be configured to play bass frequencies. Otherconfigurations are possible and depend on the number of zone players andthe type of audio. Further, a particular zone may be configured to playa 5.1 channel audio in one instance, such as when playing audio from amovie, and then dynamically switch to play stereo, such as when playingaudio from a two channel source.

In certain embodiments, two or more zone players may be sonicallyconsolidated to form a single, consolidated zone player. A consolidatedzone player (though made up of multiple, separate devices) may beconfigured to process and reproduce sound differently than anunconsolidated zone player or zone players which are paired, because aconsolidated zone player will have additional speaker drivers from whichsound may be passed. The consolidated zone player may further be pairedwith a single zone player or yet another consolidated zone player. Eachplayback device of a consolidated playback device is preferably set in aconsolidated mode.

According to some embodiments, one may continue to do any of: group,consolidate, and pair zone players, for example, until a desiredconfiguration is complete. The actions of grouping, consolidation, andpairing are preferably performed through a control interface, such asusing controller 130, and not by physically connecting and re-connectingspeaker wire, for example, to individual, discrete speakers to createdifferent configurations. As such, certain embodiments described hereinprovide a more flexible and dynamic platform through which soundreproduction may be offered to the end-user.

Sources of audio content to be played by zone players 102-124 arenumerous. Music from a personal library stored on a computer ornetworked-attached storage (NAS) may be accessed via the data network128 and played. Internet radio stations, shows, and podcasts may beaccessed via the data network 128. Music services which let a userstream and download music and audio content may be accessed via the datanetwork 128. Further, music may be obtained from traditional sources,such as a turntable or CD player, via a line-in connection to a zoneplayer, for example. Audio content may also be accessed through AirPlay™wireless technology by Apple, Inc., for example. Audio content receivedfrom one or more sources may be shared amongst the zone players 102 to124 via the data network 128 and/or the controller 130. Theabove-disclosed sources of audio content are referred to herein asnetwork-based audio information sources. However, network-based audioinformation sources are not limited thereto.

III. Example Playback Device

Referring now to FIG. 4, there is shown an example functional blockdiagram of a zone player 400 in accordance with an embodiment. The zoneplayer 400 of FIG. 4 includes a network interface 402, a processor 408,a memory 410, an audio processing component 412, a module 414, an audioamplifier 416, a speaker unit 418 coupled to the audio amplifier 416,and a location component 424. FIG. 2A shows an example illustration ofsuch a zone player. Other types of zone players may not include thespeaker unit 418 (e.g., such as shown in FIG. 2B) or the audio amplifier416 (e.g., such as shown in FIG. 2C). In addition, other types of zoneplayers may not include an integrated location component 424, butinstead, may communicate with an external location component 424 via thenetwork interface 402, for example. Further, it is contemplated the zoneplayer 400 may be integrated into another component. For example, thezone player 400 could be constructed as part of a lamp for indoor oroutdoor use.

Referring back to FIG. 4, the network interface 402 facilitates a dataflow between zone players and other devices on a data network (e.g., thedata network 128 of FIG. 1) and the zone player 400. In someembodiments, the network interface 402 may manage the assembling of anaudio source or file into smaller packets which are to be transmittedover the data network or reassembles received packets into the originalsource or file. In some embodiments, the network interface 402 mayfurther handle the address part of each packet so it gets to the rightdestination or intercepts packets destined for the zone player 400.Accordingly, in certain embodiments, each of the packets includes anInternet Protocol (IP)-based source address as well as an IP-baseddestination address.

In some embodiments, the network interface 402 may include one or bothof a wireless interface 404 and a wired interface 406. The wirelessinterface 404, also referred to as a Radio Frequency (RF) interface,provides network interface functions for the zone player 400 towirelessly communicate with other devices (e.g., other zone player(s),speaker(s), receiver(s), component(s) associated with the data network128, and so on) in accordance with a communication protocol (e.g., anyof the wireless standards IEEE 802.11a, 802.11b, 802.11g, 802.11n, or802.15). To receive wireless signals and to provide the wireless signalsto the wireless interface 404 and to transmit wireless signals, the zoneplayer 400 of FIG. 4 includes one or more antennas 420. The wiredinterface 406 provides network interface functions for the zone player400 to communicate over a wire with other devices in accordance with acommunication protocol (e.g., IEEE 802.3). In some embodiments, a zoneplayer includes both of the interfaces 404 and 406. In some embodiments,a zone player 400 includes only the wireless interface 404 or the wiredinterface 406.

In some embodiments, the processor 408 is a clock-driven electronicdevice configured to process input data according to instructions storedin memory 410. The memory 410 is data storage which may be loaded withone or more software modules 414, which may be executed by the processor408 to achieve certain tasks. In the illustrated embodiment, the memory410 is a tangible machine readable medium storing instructions which maybe executed by the processor 408. In some embodiments, a task might befor the zone player 400 to retrieve audio data from another zone playeror a device on a network. In some embodiments, a task might be for thezone player 400 to send audio data to another zone player or device on anetwork. In some embodiments, a task might be for the zone player 400 tosynchronize playback of audio with one or more additional zone players.In some embodiments, a task might be to pair the zone player 400 withone or more zone players to create a multi-channel audio environment.Additional or alternative tasks may be achieved via the one or moresoftware modules 414 and the processor 408.

The location component 424 may include one or more sensors,transmitters, receivers, detectors, processors, and so on. In order todetermine the position of the listener or a plurality of listeners, thelocation circuit 424 receives location data from sensors. Based on thereceived location data, the location component 424 is able to generate alistener location, a number of listener locations, and/or a locationpoint based on the number of listener locations. To gather dataindicative of the position of the listener and/or listeners, thelocation circuit 424 communicates with the sensors. In some embodiments,a listener location is a location within a room or area. In someembodiments, a listener location is a location with a home or officespace. In some embodiments, a listener location is a location relativeto one or more zone players. In some embodiments, a listener locationmay be another predefined location.

In some embodiments, the location data is communicated to processor 408for processing. In some embodiments, the location data is communicatedto audio processing component 412 for processing. In other embodiments,the location data is processed by the location component 424. Thelocation data may be processed by any other device or component capableof performing calculations.

In one embodiment, the location component 424 includes an image capturedevice such as a camera. The camera captures image frames with imagecharacteristics. In such embodiments, the captured image framecharacteristics include luminance and/or shadowing qualities. Thecaptured image frame characteristics are then communicated to aprocessor for generating localization information. By comparing changesin luminance and shadowing characteristics of the captured image frames,the processor is able to detect the position of the listener to generatelocalization information. The generated localization information is thencommunicated to the audio processing circuit 412.

In another embodiment, the image capture device included in the locationcomponent 424 includes an infrared (IR) camera. In such embodiments, theIR camera captures image frame characteristics, including body heatcharacteristics. The captured image frame characteristics are thencommunicated to a processor for generating localization information. Bycomparing changes in body heat signatures, the processor is able togenerate localization information. The generated localizationinformation is then communicated to the audio processing component 412.

In another embodiment, an IR transmitter may be carried by the listeneras a remote and/or controller (not shown). The remote may be a cellularphone, a personal digital assistant (PDA), or another portable devicecapable of transmitting an IR signal. The transmitted IR signals may bereceived by an IR receiver, such as an IR diode, included in thelocation component 424. These signal pulses are then gathered andcommunicated to the processor for generating localization data. Byanalyzing the phase shifts and the time delays associated with theinputted IR signals and the location of the IR receivers, the processoris able to triangulate the position of the listener. This localizationinformation is then communicated to the audio processing circuit 412.

In another embodiment, the location component 424 includes one or moremicrophones. The microphones are able to gather acoustic waveinformation from the listener. In some embodiments, the acoustic waveinformation is generated by the listener. For instance, the listener maygenerate oratory signals which are received by the microphones includedin the location component 424 as acoustic wave information. In someembodiments, the listener carries a remote, such as a cellular phone, aPDA, or another portable device, producing an auditory tone detected bythe microphones included in the location component 424. The auditorytone may be in the human audible range, or may be outside of the audiblerange. By determining the time delay in the acoustic wave informationreceived at the microphones, the processor is able to triangulate theposition of the listener. This localization information is thencommunicated to the audio processing circuit 412.

In another embodiment, the listener carries a remote, such as a cellularphone, PDA, or another portable device, which transmits a controlpacket. Included in the control packet is an associated Received SignalStrength Indicator (RSSI) signal with a timestamp. The control packet isthen received by sensors in the location component 424 of the zoneplayer 400. The gathered control packets are then communicated to theprocessor. By comparing the information included in the received controlpacket from the listener with an associated RSSI signal and the timedelay, the processor is able to triangulate the position of thelistener. This localization information is then communicated to theaudio processing circuit 412.

In another embodiment, the location component 424 includes sensors toreceive data packets. Wireless signals, for example, transmitted at 2.4GHz frequency, are absorbed by the human body. The data packets receivedby the sensors are able to detect changes in the strength of the signalreceived by the sensor. By comparing the expected signal strength withthe actual received signal strength, the processor is able totriangulate the relative position of the listener. This localizationinformation is then communicated to the audio processing component 412.

The audio processing component 412 may include one or moredigital-to-analog converters (DAC), an audio preprocessing component, anaudio enhancement component or a digital signal processor, and so on. Incertain embodiments, the audio retrieved via the network interface 402is processed and/or intentionally altered by the audio processingcomponent 412. In some examples, the audio processing component 412filters audio signals differently for different speakers 418. Further,the audio processing component 412 may produce analog audio signals. Theprocessed analog audio signals are then provided to the audio amplifier416 for play back through speakers 418. In addition, the audioprocessing component 412 may include necessary circuitry to processanalog or digital signals as inputs to play from zone player 400, sendto another zone player on a network, or both play and send to anotherzone player on the network. An example input includes a line-inconnection (e.g., an auto-detecting 3.5 mm audio line-in connection).

The audio amplifier 416 is a device which amplifies audio signals to alevel for driving one or more speakers 418. The one or more speakers 418may include an individual transducer (e.g., a “driver”) or a completespeaker system which includes an enclosure including one or moredrivers. A particular driver may be a subwoofer (for low frequencies), amid-range driver (middle frequencies), and a tweeter (high frequencies),for example. An enclosure may be sealed or ported, for example.

A zone player 400 may also be referred to herein as a playback device.An example playback device includes a Sonos® Play:3, which ismanufactured by Sonos, Inc. of Santa Barbara, Calif. The Play:3 is anexample zone player with a built-in amplifier and speakers. Inparticular, the Play:3 is a three-driver speaker system which includes atweeter and two mid-range speakers (also referred to as drivers). Whenplaying audio content via the Play:3, the left audio data of a track isoutput from the left mid-range speaker, the right audio data of a trackis output from the right mid-range driver, and the tweeter outputscenter or both left and right audio data for a track. Audio fromInternet radio stations, online music and video services, downloadedmusic, analog audio inputs, television, DVD, and so on, may be playedfrom a Sonos® Play:3. While the Play:3 is an example of a zone playerwith speakers, it is understood a zone player with speakers is notlimited to one with a certain number of speakers (e.g., three speakersas in the Play:3), but rather may contain one or more speakers. Further,a zone player may be part of another device, which might even serve apurpose different than audio (e.g., a lamp).

IV. Example Controller

Referring now to FIG. 5, there is shown an example controller 500, whichmay correspond to the controlling device 130 in FIG. 1. The controller500 may be used to facilitate the control of multi-media applications,automation and others in a system. In particular, the controller 500 isconfigured to facilitate a selection of a plurality of audio sourcesavailable on the network and enable control of one or more zone players(e.g., the zone players 102-124 in FIG. 1) through a wireless networkinterface 508. According to one embodiment, the wireless communicationsis based on an industry standard (e.g., infrared, radio, wirelessstandards IEEE 802.11a, 802.11b 802.11g, 802.11n, or 802.15). Further,when a particular audio is being accessed via the controller 500 orbeing played via a zone player, a picture (e.g., album art) or any otherdata, associated with the audio source may be transmitted from a zoneplayer or other electronic device to the controller 500 for display.

The controller 500 is provided with a screen 502 and an input interface514 which allows a user to interact with the controller 500, forexample, to navigate a playlist of many multimedia items and to controloperations of one or more zone players. The screen 502 on the controller500 may be a liquid crystal display (LCD) screen, for example. Thescreen 500 communicates with and is commanded by a screen driver 504controlled by a microcontroller (e.g., a processor) 506. The memory 510may be loaded with one or more application modules 512 which may beexecuted by the microcontroller 506 with or without a user input via theuser interface 514 to achieve certain tasks. In some embodiments, anapplication module 512 is configured to facilitate grouping a number ofselected zone players into a zone group and synchronizing the zoneplayers for audio play back. In some embodiments, an application module512 is configured to control the audio sounds (e.g., volume) of the zoneplayers in a zone group. In operation, when the microcontroller 506executes one or more of the application modules 512, the screen driver504 generates control signals to drive the screen 502 to display anapplication specific user interface accordingly.

The controller 500 includes a network interface 508 which facilitateswireless communication with a zone player. In some embodiments, thecommands such as volume control and audio playback synchronization aresent via the network interface 508. In some embodiments, a saved zonegroup configuration is transmitted between a zone player and acontroller via the network interface 508. The controller 500 may controlone or more zone players, such as 102-124 of FIG. 1. There may be morethan one controller for a particular system. Further, a controller maybe integrated into a zone player.

It should be noted other network-enabled devices such as an iPhone®,iPad® or any other smart phone or network-enabled device (e.g., anetworked computer such as a PC or Mac®) may also be used as acontroller to interact or control zone players in a particularenvironment. In some embodiments, a software application or upgrade maybe downloaded onto a network enabled device to perform the functionsdescribed herein.

In some embodiments, a user may create a zone group including at leasttwo zone players from the controller 500. The zone players in the zonegroup may play audio in a synchronized fashion, so all of the zoneplayers in the zone group play back an identical audio source or a listof identical audio sources in a synchronized manner so no (orsubstantially no) audible delays or hiccups could be heard. Similarly,in some embodiments, when a user increases the audio volume of the groupfrom the controller 500, the signals or data of increasing the audiovolume for the group are sent to one of the zone players and causesother zone players in the group to be increased together in volume.

A user via the controller 500 may group zone players into a zone groupby activating a “Link Zones” or “Add Zone” soft button, or de-grouping azone group by activating an “Unlink Zones” or “Drop Zone” button. Forexample, one mechanism for ‘joining’ zone players together for audioplay back is to link a number of zone players together to form a group.To link a number of zone players together, a user may manually link eachzone player or room one after the other. For example, assume there is amulti-zone system which includes the following zones: Bathroom, Bedroom,Den, Dining Room, Family Room, and Foyer.

In some embodiments, a user may link any number of the six zone players,for example, by starting with a single zone and then manually linkingeach zone to the first zone.

In some embodiments, a set of zones may be dynamically linked togetherusing a command to create a zone scene or theme (subsequent to firstcreating the zone scene). For instance, a “Morning” zone scene commandmay link the Bedroom, Office, and Kitchen zones together in one action.Without this single command, the user would need to manually andindividually link each zone. The single command might include a mouseclick, a double mouse click, a button press, a gesture, or some otherprogrammed action. Other kinds of zone scenes may be programmed.

In some embodiments, a zone scene may be triggered based on time (e.g.,an alarm clock function). For instance, a zone scene may be set to applyat 8:00 am. The system may link appropriate zones automatically, setspecific music to play, and then stop the music after a definedduration. Although any particular zone may be triggered to an “On” or“Off” state based on time, for example, a zone scene enables any zone(s)linked to the scene to play a predefined audio (e.g., a favorable song,a predefined playlist) at a specific time and/or for a specificduration. If, for any reason, the scheduled music failed to be played(e.g., an empty playlist, no connection to a share, failed UniversalPlug and Play (UPnP), no Internet connection for an Internet Radiostation, and so on), a backup buzzer may be programmed to sound. Thebuzzer may include a sound file stored in a zone player, for example.

FIG. 6 shows an example pair of zone players 602, 604 havingmid-tweeter-mid (MTM) speaker arrangements, including audio filters, andconfigured as a stereo pair. Either of the example zone players 602, 604may be implemented by the zone player 400 of FIG. 4. In particular, eachof the example zone players 602, 604 includes an audio processingcircuit (e.g., the audio processing circuit 412 of FIG. 4) to implementa set of audio filters, and a plurality of speakers (e.g., the speakers418 of FIG. 4) to implement a corresponding set of speakers or audioreproduction devices.

An MTM speaker arrangement includes two mid-range speakers 606, 608,610, 612 (e.g., speakers having a diameter between about 3.5 inches and6.75 inches, operating in the approximate frequency range of 300-5000Hz) and a high-range speaker, also known as a tweeter 614, 611 (e.g.,3.5 inch diameter or smaller, operating in the approximate frequencyrange of 2,000-20,000 Hz) per zone player 602, 604. The example zoneplayers 602, 604 of FIG. 6 may be oriented horizontally, where thecenters of the mid-range speakers are substantially level in ahorizontal direction, and/or vertically, where the centers of themid-range speakers are substantially aligned in a vertical direction.The example mid-range speakers 606, 608 are spaced so the centers of thespeakers 606, 608 are approximately one-half wavelength of a selectedcenter frequency (e.g., λ₀/2) apart. An example center frequency λ₀which may be used to determine the spacing of the example pairs ofmid-range speakers 606, 608 and 610, 612 is 1,000 Hz, which has awavelength of about 344 millimeters (e.g., at sea level at about 20degrees Celsius). The example tweeter 614 is positioned between theexample mid-range speakers 606, 608.

The example zone players 602, 604 include respective audio filters 616,618. As mentioned above, the example audio filters 616, 618 may beimplemented using digital audio processing circuitry, such as a digitalaudio processor or other digital processing unit. The following examplewill be described with reference to the example audio filter 616 of FIG.6. However, the description of the audio filter 616 is also applicableto the example audio filter 618. The operation of the example zoneplayers 602, 604 as a stereo pair with respect to the audio filters 616,618 is also discussed below. The example zone players 602, 604 may alsobe operated in other multiple-device arrangements. As used herein“multiple-device” refers to separate sets of speakers, such asmultiple-MTM speaker arrangements, and not merely multiple speakers inthe same device.

The example audio filter 616 of FIG. 6 is an active filter, whichfilters the received audio information prior to amplification. Theexample audio filter 616 includes an audio preprocessing block 620, afirst mid-range filter 622, a second mid-range filter 624, and a tweeterfilter 626. The example audio preprocessing block 620 may include, forexample, audio decoding to decompress and/or otherwise convert an audioinformation (e.g., an audio file) from a storage format (e.g.,compressed) to audio information in a playback format. The audiopre-processing block 620 provides the audio information to the examplefilters 622-626 for processing.

Some MTM speaker arrangements experience a “narrowing” phenomenon, inwhich a listener positioned straight in front of the speakers willexperience the audio differently than a listener positioned to the leftor the right of the speakers. This phenomenon is particularly acute foraudio frequencies around the center frequency f₀ (e.g., the frequency onwhich the spacing of the mid-range speakers is based). In some cases,certain frequencies are completely canceled out in some positionsrelative to the speaker. While this behavior may be desirable in somecircumstances, such as when the MTM speakers are oriented vertically(which reduces reflections and/or echoes off of the ceilings andfloors), such behavior may be undesirable in others, such as when theMTM speakers are oriented horizontally (which results in a limited rangeof positions in which the frequency response is consistent and the audiosounds substantially as intended). Unlike such known MTM speakerarrangements, the example zone players 602, 604 of FIG. 6 reduce oreliminate the narrowing phenomenon and increase the angular audibilityrange (e.g., the range of angles measured from straight in front of thespeaker) in which the frequency response is consistent and the soundsfrom the speakers are heard substantially as intended.

In the example of FIG. 6, the audio filter 616 processes the audio basedon the configuration of the zone player 602 in the stereo pair. Inparticular, the zone player 602 is set up as the left speaker (whenviewing from the front). Additionally, the zone player 602 is configuredwith a horizontal orientation. Thus, the zone player 602 is aware thespeaker 606 is the left mid-range speaker and the speaker 608 is theright mid-range speaker for the left zone player 602 of the stereo pair(when viewing from the front). Based on this configuration information,the example audio filter 616 applies a first filtering configuration(e.g., the first mid-range filter 620) to the left (e.g., outer)mid-range speaker 606 and applies a second filtering configuration(e.g., the second mid-range filter 624) to the right (e.g., inner)mid-range speaker 608.

The example audio filter 618 also includes audio preprocessing 628, afirst mid-range filter 630, a second mid-range filter 632, and a tweeterfilter 634. Like the audio filter 616, the audio filter 618 applies thedifferent filtering configurations to the example mid-range filters 610,612 based on configuration information for the zone player 604 (e.g.,physical orientation, status as right/left speaker of a stereo pair,etc.). In the example of FIG. 6, the audio filter 618 applies the firstmid-range filter 630 to the right (e.g., outer) mid-range speaker 612and applies the second mid-range filter 632 to the left (e.g., inner)mid-range speaker 610. The example audio filters 616, 618 result in thezone players 602, 604 steering audio and expanding the angular field ofaudibility relative to known MTM speakers.

FIG. 7 is a flow chart describing an example method for calibrating thesound field based on the position of the listener. Operation begins whena zone player is initiated for playback (Block 700). Once initiated, thezone player begins to gather location data (Block 701). Location data iscollected by the zone player through sensors included in locationcomponent 424, described above in FIG. 4.

In some embodiments, the location information captured by the sensorsrepresents image frame characteristics. In some embodiments, thelocation data captured by the sensors represents body heatcharacteristics. In some embodiments, the location information collectedby the sensors is radio frequency signals. In some embodiments, thelocation data collected by the sensors are data packets.

Once the location information is gathered by the location component 424,the location information is processed (Block 710). The gathered locationdata is processed to determine the position of the listener. In someembodiments, this processed location data defines a “sweet spot” wherethe sound fields received by the listener are optimized to provide thelistener with the most enjoyable playback experience (e.g., optimizedimaging, optimized equalization values, optimized volume levels, and soon). In some embodiments, the gathered location data determines thepresence of multiple listeners in the listening zone. In some suchembodiments, the processed sweet spot adjusts the audio characteristicsof the retrieved audio to generate a sound field most suitable for theplurality of detected listeners. For example, in one embodiment, if twolisteners were detected in a zone area, the processed sweet spot wouldengulf both listeners and optimize the audio characteristics of thesound field to account for the two listeners.

In some embodiments, the location data is communicated to processor 408of FIG. 4 for processing. In some embodiments, the location data iscommunicated to audio processing component 412 for processing. In otherembodiments, the location data is processed by the location component424. The location data may be processed by any other device or componentcapable of performing calculations. Through the use of one or moretriangulation algorithms and the gathered location information, theposition of the listener may be calculated.

The position of the listener is then communicated to the audioprocessing component 412 of FIG. 4 as localization signals (Block 720).As described above with respect to FIG. 4, the audio processingcomponent 412 may include an audio preprocessing component, an audioenhancement component or a digital signal processor, and so on. Theaudio retrieved by the zone player via the network interface 402 isprocessed and/or intentionally altered by the audio processing component412. In some embodiments, the localization signals may be communicatedto and received by a zone player in the same room as a listener or groupof listeners. In some embodiments, the localization signals may becommunicated to and received by a zone player or zone players with nolisteners in the listening area. In some such embodiments, thelocalization signals may be used by the zone player or zone players toadjust the audio characteristics of the respective output sound field.

The audio processing component 412 then processes and/or intentionallyalters the audio retrieved via the network interface 402 in combinationwith the localization signals (Block 725). In some examples, the audioprocessing component 412 filters the audio signals differently fordifferent speakers. The processed audio signals output by the audioprocessing component 412 represent audio characteristics of a soundfield adjusted for the position of the listener. In some embodiments,the audio signal may be processed based on a factory set of parameters.In some embodiments, the audio signal may be processed based on alistener set of parameters. In some embodiments, the audio signal may beprocessed based on a combination of factory and listener sets ofparameters. For example, in one embodiment, more or less bass may beoutput depending on how close a listener is to a particular zone player.

In some examples, the processed audio signals also include additionallistener preferences, such as volume levels. For example, in oneembodiment, while a song is playing in synchrony in the Dining Room andFamily Room of FIG. 1, but the listener is localized only in the FamilyRoom, the listener preference may be to automatically lower the volumeof the zone player in the Family Room and raise the volume of the zoneplayer in the Dining Room. In some such embodiments, lowering andraising the volume in this manner may result in a more omni-directionalsound field for the listener.

The processed audio signals are then provided to an audio amplifier forplayback through speakers (Block 730). In some embodiments, theprocessed audio signals are communicated to audio amplifier 416 of FIG.4 for playback through speakers 418 of FIG. 4. In addition, the audioprocessing component 412 may include necessary circuitry to play fromzone player 400, send to another zone player on a network, or both playand send to another zone player on the network.

Referring back to FIG. 1, the listener localization may take place in amultiple-device configuration. For example, the Home Theater Room ofFIG. 1 includes at least three zone players. As described above, if azone or room contains more than one zone player, then the zone playersmay be synchronized to play the same audio source, or the zone playersmay be paired to play separate channels. When a zone with multiple zoneplayers is configured, a master zone player is assigned. For instance,in one embodiment, the master zone player may be the first zone playerconfigured in the zone. In another embodiment, the master zone player isselected by the listener. In another embodiment, the master zone playeris randomly assigned.

For illustrative purposes, zone player 120 will be labeled as the masterzone player. As a result, when zone players 116 and 118 are synched tothe Home Theater Room zone, they are labeled as slave zone players. Oncea zone player is labeled a master zone player, all slave zone players inthe zone communicate information with the master zone player.

Continuing with the example, slave zone players 116 and 118 nowcommunicate all of their information to master zone player 120. Includedin the information communicated with master zone player 120 is thelocation data gathered by the location component 424 of each respectivezone player. As a result, master zone player 120 now has the locationinformation from each of the slave zone players 116 and 118, as well asthe location information collected by the location component 424 of zoneplayer 120. Master zone player 120 is then able to triangulate thelocation of the listener with all of the aggregated information. Masterzone player 120 then communicates the respective localizationinformation to each of the slave zone players 116 and 118. Each of thezone players 116-120 communicates the received localization informationto the audio processing circuit 412 of each respective zone player. As aresult, the audio characteristic of the output sound field of each zoneplayer 116-120 is optimized to produce the best listening environmentfor the listener. For example, the volume level of the zone player orzone players nearest the position of the listener may be reduced basedon the position of the listener in relation to the other zone player orzone players.

In some embodiments, the master zone player gathers the locationinformation continuously, or near continuously, resulting in real-time,or substantially real-time, calibration of the sound field as each zoneplayer tracks the listener throughout the listening zone. As thelistener moves around in the listening zone, the sweet spot may beadjusted to track the position of the listener. In some embodiments, themaster zone player gathers the location information from the slave zoneplayers periodically. For example, the master zone player may gather thelocation information five times in one second. In some embodiments, themaster zone player gathers the location information whenever one of thezone players in the listening zone detects a change in the position ofthe listener. For example, while the listener sits in a chair, all threezone players 116-120 remain idle; if zone player 116 detects movement bythe listener, zone player 116 sends a signal to master zone player 120,which then gathers the location information from all of the zone players116-120 in order to triangulate the position of the listener.

FIG. 8 is a flow chart describing an example method for listenerlocalization with a multiple-device configuration in a multiple-zonescene. For example, the “Morning” zone scene described above links zoneplayers 112, 110 and 102 in the Bedroom, Office and Kitchen zones,respectively. Operation begins when a zone scene is selected forplayback (Block 801). In some embodiments, playback may be initiatedthrough the selection of an audio song with the controller. In anotherembodiment, playback may be automatically initiated when a preset alarmis activated. Similar to the single-zone, multiple-device configuration,when the zone players are being linked, a master zone player is assigned(Block 805). As previously described, in some embodiments, the masterzone player may be the first zone player configured in the zone. Inanother embodiment, the master zone player is selected by the listener.In another embodiment, the master zone player is randomly assigned.

For illustrative purposes, zone player 112 in the Bedroom zone islabeled the master zone player. If a second zone player is linked to thezone scene (Block 810), then the second zone player is labeled a slavezone player (Block 815). The method waits to see if another zone playeris linked with the zone scene (Block 820), and if so, the system returnsto Block 815 to label another zone player. Continuing with the example,when zone player 110 is linked with the “Morning” zone scene, it islabeled as a slave zone player (Block 815). The additional linking ofzone player 102 in the Kitchen zone returns the method to Block 815,where zone player 102 is also labeled a slave zone player.

In another embodiment, no additional zone players are determined atBlock 810 and the method proceeds to Block 825. In another embodiment,no additional zone players are determined at Block 820 and the methodproceeds to Block 825.

Continuing with the example, while in the Bedroom, the listener selectsa song to play with controller 130 of FIG. 1. As a result, master zoneplayer 112 and slave zone players 110 and 102 begin playing the song insynchrony with each other, as described above. At Block 825, all threezone players (112, 110 and 102) perform a location scan. As describedabove, the location scan may be performed through a variety of sensors.In some embodiments, the sensors are cameras. In another embodiment, thesensors are IR cameras. In another embodiment, the sensors aremicrophones. In another embodiment, the sensors are data packetreceivers.

Once each zone player has completed its location scan, the location datais communicated to the master zone player (Block 830). In the currentexample, master zone player 112 gathers the location information fromeach of the zone players linked in the “Morning” zone scene, zoneplayers 112, 110 and 102. Master zone player 112 then processes thelocation information with a triangulation algorithm to determine theposition of the listener with respect to each of the zone players in thezone scene. In some embodiments, the master zone player 112 communicatesa status update to a user, such as through controller 300 of FIG. 3. Insome such embodiments, the status update may include informationregarding which zone players are active. In other such embodiments, thestatus update may indicate any changes to the sound field due to theposition of a listener. In other such embodiments, the status update mayindicate other information being monitored by the master zone player.While triangulating the position of the listener, the master zone playeris able to determine there is no listener within the listening zones ofzone players 110 and 102 (Block 835). Since there is a listener withinthe listening zone of zone player 112, localization information iscommunicated to the zone player (Block 840). Zone player 112 adjusts theaudio characteristics of the sound field outputted from zone player 112as described above in a single-zone, single-device configuration (Block845). Zone player 112 then performs another location scan (Block 850)and sends the location information back to the master zone player forgathering and processing (Block 830). In some embodiments, as thelistener moves around the room, the “sweet spot” is adjusted to trackthe position of the listener.

In another embodiment, the location information communicated to themaster zone player described no listener present in the listening area(Block 835). For instance, since the listener is located in the Bedroom,the zone players in the Office zone and the Kitchen zone are unable tolocate a listener. The master zone player then communicates a defaultsound field command along with the localization information to the zoneplayer (Block 860). In some embodiments, the default sound field ispreset by the listener. In some embodiments, the default sound fieldwhen no listener is located within the listening zone is to adjust theaudio characteristics of the sound field so the volume level isdecreased to a minimal level and the other audio characteristics returnto a default setting as if the listener were sitting in the middle ofthe room. In some embodiments, the default sound field when no listeneris located within the listening zone is to decrease the volume level ofthe speakers to the lowest setting. In some embodiments, the defaultsound field when no listener is located within the listening zone is toturn off the zone player so no sound field is output by the zone player.In some embodiments, the default audio setting when no listener islocated within the listening zone is to make no changes to the soundfield and leave the audio characteristics of the output sound field thesame as they were previously set. Each zone player then adjusts therespective audio characteristics of the outputted sound field to matchthe default sound field command (Block 865).

The zone player then moves to Block 866, where it waits to perform thenext location scan. In some embodiments, the default sound field commandcommunicated to the zone players in Block 860 may also modify thefrequency of location scans performed by the zone player. In someembodiments, since slave zone players 110 and 102 have not detected anychange in their localization information, they send no locationinformation to master zone player 112. In some embodiments, slave zoneplayers 110 and 102 do less frequent location scans when no listener waspreviously detected in their respective listening zones. For instance,slave zone players 110 and 102 perform listener scans half as often asthey previously were scanning. In some embodiments, slave zone players110 and 102 perform localization scans more frequently than previouslyperformed. For instance, slave zone players 110 and 102 perform twice asmany localization scans than previously performed. In some embodiments,slave zone players 110 and 102 continue to send location information tomaster zone player 112 with no change in the frequency of locationscans. After the waiting period is completed, the zone player thenperforms a new location scan (Block 870).

In some embodiments, the location scan performed in Block 870 reveals achange in the location information (Block 875) and the new locationinformation is communicated to the master zone player in Block 830. Forexample, in one embodiment, zone players 110 and 102 were turned off sono sound field was output by the respective zone players at Block 865.At Block 870, zone player 110 reveals the presence of a listener in thezone player 110 listening area. Zone player 110 then resumes audioplayback and communicates the new location information to the masterzone player (Block 830).

In some embodiments, the location scan performed in Block 870 reveals nochange in the location information (Block 875) and the method returns toBlock 866 to wait to perform the next location scan.

In another embodiment, listener information communicated to the masterzone player 112 in Block 830 determines the presence of a listener inthe Kitchen zone as well as the Bedroom zone. In such an example, masterzone player 112 and slave zone player 102 may follow the path from Block835 to Block 840, as described above. As a result, zone players 112 and102 output adjusted sound fields optimized for each listener. Slave zoneplayer 110 may continue the path from Block 835 to Block 860, asdescribed above.

In another embodiment, location scans are conducted by zone players notin the currently playing zone scene. For example, while the Morning zonescene is playing in synchrony through zone players 112, 110 and 102,zone player 114 in the Bathroom zone also performs a location scan. Insome embodiments, zone player 114 detects the presence of a listener inthe Bathroom zone listening area and sends the location information tothe master zone player 112. Master zone player 112 may then determine ifan automatic synching feature is enabled by a listener. In someembodiments, the automatic synching feature is enabled and master zoneplayer 112 automatically adds zone player 114 to the zone scene andcontinues with Block 815. In some embodiments, the automatic synchingfeature is disabled and master zone player 112 disregards the locationinformation provided by zone player 114.

In view of the foregoing, it should be apparent disclosed examplesystems, methods and apparatus may be used to provide a media playbackdevice having improved audio quality and perception. Example systems,methods, and apparatus localize the position of the listener and thenfilter audio signals for outputting a sound field with audiocharacteristics optimized for the position of the listener.

Various inventions have been described in sufficient detail with acertain degree of particularity. It is understood to those skilled inthe art the present disclosure of embodiments has been made by way ofexamples only and numerous changes in the arrangement and combination ofparts may be resorted without departing from the spirit and scope of thepresent disclosure as claimed. While the embodiments discussed hereinmay appear to include some limitations as to the presentation of theinformation units, in terms of the format and arrangement, theembodiments have applicability well beyond such embodiment, which may beappreciated by those skilled in the art. Accordingly, the scope of thepresent disclosure is defined by the appended claims rather than theforgoing description of embodiments.

We claim:
 1. A playback device comprising: one or more speakers; atleast one amplifier configured to drive the one or more speakers; one ormore location sensors comprising a network interface; one or moreprocessors comprising a digital signal processor; and a housing carryingthe one or more speakers, the at least one amplifier, the one or morelocation sensors, the one or more processors, and data storage forstoring instructions that when executed cause the playback deviceperform functions comprising: detecting, at a first time, a first numberof listeners in a listening area, wherein detecting the first number oflisteners comprises receiving, via the network interface of the one ormore location sensors, network packets transmitted from a mobile deviceassociated with a first listener, wherein the detected first number oflisteners is one; determining a first audio characteristic that adjustsa sound field generated by the one or more speakers to create a firstsweet spot that includes a location of the first listener relative tothe playback device; processing, via the digital signal processor, anaudio signal for playback according to the first audio characteristic;playing the processed audio signal via the one or more speakers and theat least one amplifier according to the first audio characteristic;while processing the audio signal for playback according to the firstaudio characteristic, detecting, at a second time, a second number oflisteners in the listening area, wherein detecting the second number oflisteners comprises receiving, via the network interface of the one ormore location sensors, network packets transmitted from respectivemobile devices associated with two or more second listeners, and whereinthe detected second number of listeners is greater than one; determininga second audio characteristic that adjusts the sound field generated bythe one or more speakers to create a second sweet spot that includesrespective locations of the two or more second listeners; afterdetermining the second audio characteristic, processing, via the digitalsignal processor, the audio signal for playback according to the secondaudio characteristic; and playing the processed audio signal via the oneor more speakers and the at least one amplifier according to the secondaudio characteristic.
 2. The playback device of claim 1, wherein the oneor more location sensors further comprise an image capture device,wherein detecting the first number of listeners in the listening areacomprises receiving image data representing the listening area at thefirst time, and wherein detecting the second number of listeners in thelistening area comprises receiving image data representing the listeningarea at the second time.
 3. The playback device of claim 1, wherein theone or more location sensors further comprise a microphone, whereindetecting the first number of listeners in the listening area comprisesreceiving microphone data at the first time, and wherein detecting thesecond number of listeners in the listening area comprises receivingmicrophone data at the second time.
 4. The playback device of claim 1,wherein the first audio characteristic comprises a first audio filter,and wherein the second audio characteristic comprises a second audiofilter.
 5. The playback device of claim 1, wherein the first audiocharacteristic comprises a first volume level, and wherein the secondaudio characteristic comprises a second volume level.
 6. The playbackdevice of claim 1, wherein the playback device is a first playbackdevice, and wherein the functions further comprise: sending, via thenetwork interface, an indication of the second number of listeners inthe listening area to a second playback device, thereby causing thesecond playback device to adjust audio playback from the first audiocharacteristic to the second audio characteristic based on the detectedsecond number of listeners in the listening area.
 7. The playback deviceof claim 1, wherein determining the second audio characteristic thatadjusts the sound field generated by the one or more speakers to createthe second sweet spot that includes respective locations of the two ormore second listeners comprises determining a particular second audiocharacteristic that enlarges the first sweet spot to create the secondsweet spot that includes respective locations of the two or more secondlisteners.
 8. Tangible, non-transitory, computer-readable media havinginstructions encoded therein, wherein the instructions, when executed byone or more processors, cause a playback device to perform functionscomprising: detecting, at a first time, a first number of listeners in alistening area, wherein detecting the first number of listenerscomprises receiving, via a network interface of one or more locationsensors, network packets transmitted from a mobile device associatedwith a first listener, wherein the detected first number of listeners isone, and the playback device comprises a housing carrying the one ormore location sensors; determining a first audio characteristic thatadjusts a sound field generated by one or more speakers of the playbackdevice to create a first sweet spot that includes a location of thefirst listener relative to the playback device; processing, via adigital signal processor of the playback device, an audio signal forplayback according to the first audio characteristic, wherein thehousing carries the digital signal processor; while processing the audiosignal for playback according to the first audio characteristic,detecting, at a second time, a second number of listeners in thelistening area, wherein detecting the second number of listenerscomprises receiving, via the network interface of the one or morelocation sensors, network packets transmitted from respective mobiledevices associated with two or more second listeners, and wherein thedetected second number of listeners is greater than one; determining asecond audio characteristic that adjusts the sound field generated bythe one or more speakers to create a second sweet spot that includesrespective locations of the two or more second listeners; afterdetermining the second audio characteristic, processing, via the digitalsignal processor, the audio signal for playback according to the secondaudio characteristic; and playing the processed audio signal via one ormore speakers and at least one amplifier according to the second audiocharacteristic, wherein the housing carries the one or more speakers andthe at least one amplifier.
 9. The tangible, non-transitory,computer-readable media of claim 8, wherein the one or more locationsensors further comprise an image capture device, wherein detecting thefirst number of listeners in the listening area comprises receivingimage data representing the listening area at the first time, andwherein detecting the second number of listeners in the listening areacomprises receiving image data representing the listening area at thesecond time.
 10. The tangible, non-transitory, computer-readable mediaof claim 8, wherein the first audio characteristic comprises a firstaudio filter, and wherein the second audio characteristic comprises asecond audio filter.
 11. The tangible, non-transitory, computer-readablemedia of claim 8, wherein the first audio characteristic comprises afirst volume level, and wherein the second audio characteristiccomprises a second volume level.
 12. The tangible, non-transitory,computer-readable media of claim 8, wherein the playback device is afirst playback device, the functions further comprising: sending, via anetwork interface, an indication of the second number of listeners inthe listening area to a second playback device, thereby causing thesecond playback device to adjust audio playback from the first audiocharacteristic to the second audio characteristic based on the detectedsecond number of listeners in the listening area.
 13. The tangible,non-transitory, computer-readable media of claim 8, wherein the one ormore location sensors further comprise a microphone, wherein detectingthe first number of listeners in the listening area comprises receivingmicrophone data at the first time, and wherein detecting the secondnumber of listeners in the listening area comprises receiving microphonedata at the second time.
 14. The tangible, non-transitory,computer-readable media of claim 8, wherein determining the second audiocharacteristic that adjusts the sound field generated by the one or morespeakers to create the second sweet spot that includes respectivelocations of the two or more second listeners comprises determining aparticular second audio characteristic that enlarges the first sweetspot to create the second sweet spot that includes respective locationsof the two or more second listeners.
 15. A method to be performed by aplayback device, the method comprising detecting, at a first time, afirst number of listeners in a listening area, wherein detecting thefirst number of listeners comprises receiving, via a network interfaceof one or more location sensors, network packets transmitted from amobile device associated with a first listener, wherein the detectedfirst number of listeners is one, and the playback device comprises ahousing carrying the one or more location sensors; determining a firstaudio characteristic that adjusts a sound field generated by one or morespeakers to create a first sweet spot that includes a location of thefirst listener relative to the playback device; processing, via adigital signal processor of the playback device, an audio signal forplayback according to the first audio characteristic, wherein thehousing carries the digital signal processor; while processing the audiosignal for playback according to the first audio characteristic,detecting, at a second time, a second number of listeners in thelistening area, wherein detecting the second number of listenerscomprises receiving, via the network interface of the one or morelocation sensors, network packets transmitted from respective mobiledevices associated with two or more second listeners, and wherein thedetected second number of listeners is greater than one; determining,via the playback device, a second audio characteristic that adjusts thesound field generated by the one or more speakers to create a secondsweet spot that includes respective locations of the two or more secondlisteners; after determining the second audio characteristic,processing, via the digital signal processor of the playback device, theaudio signal for playback according to the second audio characteristic;and playing the processed audio signal via one or more speakers and atleast one amplifier according to the second audio characteristic,wherein the housing carries the one or more speakers and the at leastone amplifier.
 16. The method of claim 15, wherein the one or morelocation sensors further comprise a microphone, wherein detecting thefirst number of listeners in the listening area comprises receivingmicrophone data at the first time, and wherein detecting the secondnumber of listeners in the listening area comprises receiving microphonedata at the second time.
 17. The method of claim 15, wherein the firstaudio characteristic comprises a first audio filter, and wherein thesecond audio characteristic comprises a second audio filter.
 18. Themethod of claim 15, wherein the first audio characteristic comprises afirst volume level, and wherein the second audio characteristiccomprises a second volume level.
 19. The method of claim 15, wherein theplayback device is a first playback device, and wherein the methodfurther comprises: sending, via the network interface, an indication ofthe second number of listeners in the listening area to a secondplayback device, thereby causing the second playback device to adjustaudio playback from the first audio characteristic to the second audiocharacteristic based on the detected second number of listeners in thelistening area.
 20. The method of claim 15, wherein determining thesecond audio characteristic that adjusts the sound field generated bythe one or more speakers to create the second sweet spot that includesrespective locations of the two or more second listeners comprisesdetermining a particular second audio characteristic that enlarges thefirst sweet spot to create the second sweet spot that includesrespective locations of the two or more second listeners.